2-Alkyl thio

Novel chiral thiolated amino alcohols have been recently synthesised and then evaluated by Vilaivan el al. as a potential new class of ligands for Cu-catalysed nitroaldol reactions. Amino alcohol ligands bearing Ai-(2-alkyl-thio)benzyl substituents provided only modest enantioselectivities (22-46% ee) while those carrying Al-2-thienylmethyl substituents provided better enantioselectivities of up to 75% ee for the nitroaldol reaction between p-nitro-benzaldehyde and nitromethane. A range of aromatic aldehydes were acceptable substrates giving moderate to high enantioselectivities of up to 88% ee, as shown in Scheme 10.32. 

Werden Isothiosemicarbazone als Amidin-Komponente verwendet, so erhalt man 2-Alkyl-thio-l-benzylidenami no-imidazole111 ... 

Alkylation at a Position a to a Heteroatom. 2-(2-Alkyl-thio)de-halogenation... 

Still in connection with the formation of isomers in these cyclization reactions, it is noteworthy that S-alkyl dithiocarbazates react with chloroacetic acid (302) and co-bromoacetophenone 84) to give 2-alkyl-thio-5,6-dihydro-4H-l, 3,4-thiadiazin-5-ones and 2-alkylthio-5-phenyl-4H-1,3,4-thiadiazines respectively. 

Simple 1-hetero-substituted allyllithium derivatives, such as 1-alkoxy-94"96, 1-alkyl-thio-50,97, 1-phenylselenyl-54,98 show insufficient regio- and simple diastereoselectivity in their reaction with aldehydes. The rcgiosclectivity is greatly enhanced in favor of the a-products by in... 

Fig. 7. UV.-absorption spectrum (in QH12 at room temperature) and fluorescence spectrum (in ether/pentane at 77 K) of an aryl alkyl thio-...

Mechanistic studies [123] have shown that thioglycosides can undergo in situ anomerization in the presence of iodonium ion catalysts. It has been demonstrated that this anomerization proceeds by intermolecular exchange of alkyl thio groups. An increase in the steric bulk of the leaving group resulted in incomplete or no anomerization. It has been proposed that this anomerization process is important for the stereochemical outcome of glycosylations [123]. 

H Hojo, S Aimoto. Polypeptide synthesis by use of an 5-alkyl thio ester of a partially protected segment. Synthesis of the DNA-binding domaine of c-Myb protein (142-1193)-NH2. Bull Chem Soc Jpn 64, 111, 1991. 

Nonracemic tra s-2-[aryl(alkyl)thio]cyclohexanols with l/ ,2/ -configuration are prepared with modest to good enantioselectivity in high yield by reaction of 1,2-epoxycyclohexane with various thiols in dichloromethane at 25 °C catalyzed by zinc L-tartrate in a heterogeneous reaction103. 

Thiophenol as the nucleophile eliminates the 1.1-substituents to form 2.4.6-triphenyl-X -phosphorin22. A similar elimination takes place if 1,1-di-alkyl-thio-X -phosphorins 169 are heated in toluene. This method is thus an excellent way to remove the dialkylamino groups which had been introduced before as protecting groups ... 

Many of the five- and six-carbon sugars, although well known, are rare, and too expensive to be used as chiral pool starting materials. David MacMillan of Caltech in an elegant series of papers (Angew. Chem. Int. Ed. 2004,43. 2152 Science 2004,305, 1752 Angew. Chem. Int. Ed. 2004,47,6722) has demonstrated a two-step route not just to protected six-carbon carbohydrates, but also to alkyl, thio and amino derivatives of those carbohydrates. 

The use of isothioureas (67 R = S-alkyl) similarly affords 3-alkyl-thio-5-chloro-l, 2,4-thiadiazoles (69 R = S-alkyl) in 35-65% yields.89,91 The method is widely applicable and has provided a variety of 5-chloro -1,2,4-thiadiazoles.9 2 9 4... 

These compounds [with the exception of (X)] show systematic losses of the two NO groups, followed by simple losses of alkyl, alkyl(thio, oxy), and... 

Thieno[3,2-d]pyrimidine-2(l//)-thiones 217-219 and -4(3//-thiones 245 were S-methylated smoothly with methyl iodide in base to the corresponding 2-methylthio (82EUP43054 89CPB1197) and 4-methylthio (86JHC 1757) compounds. 5-Alkylation of thieno[3,2-d]pyrimidin-4(3//)-one-2(l//)-thione 223 with alkyl halides in dilute sodium hydroxide solution afforded 2-alkylthio derivatives 284. Nucleophilic displacement of the alkyl-thio group in compound 284 by primary amines has also been reported (90EUP404356). 

Bei 1-Alkenen liefert die radikalische Addition ann -Markownikoff-Produktc (s. S. 189). Die Addition an Carbonyl-Verbindungen fiihrt zu Alkyl-(l-hydroxy-alkyl)-thio-phosphinsaure-O-estern ... 

Eine Variante dieses Verfahrens stellt die Umsetzung von Phosphorylchlorid mit Alkyl-thio-trimethyl-silanen dar217 z.B. ... 

Bei Umsetzung von Dithiophosphorsaure-0,S,S-triestern mit Alkoxy-trialkyl-stannanen erfolgt ein. Aikoxy-Alkyl thio-Austausch zwischen den Reaktanden. Die resultierenden Thiophosphorsaure-0,0,S-triester kdnnen in guten Ausbeuten isoliert werden (s.S. 591)752. 

Aus Thiophosphorsaure-0,0-diester-isocyanaten werden mit Alkoholen bzw. Alkan-thiolen (207Diethylether) Thiophosphorsaure-alkoxycarbonylamid- bzw. -(alkyl-thio-carbonyl)-amid-0,0-diester (80—99%) erhalten433 ... 

The action of thiophosgene on carbohydrates in the presence of base and the reaction of a sodium-carbohydrate with a suitable 0-[(alkyl-thio)thiocarbonyl] derivative both give rise to intermolecular thionocarbonates. 

In the same year, Wolfrom and Foster synthesized certain 2-0-[(alkyl-thio)thiocarbonyl] derivatives of methyl 3,4-0-isopropylidene-iS-D(and l)-arabinopyranoside and of methyl 4,6-0-benzylidene-3-0-methyl- -D-altro-pyranoside by the action of carbon disulfide on the appropriate 2-0-sodio compounds, followed by treatment with an alkyl halide. The halides used— methyl iodide and triphenylmethyl iodide—were chosen for their ability to cause (S-alkylation rather than transformation to a thionocarbonate (see p. 110). The D- and L-arabinose derivatives could be converted to 2-deoxy-o-eri/ /iro-pentose (see p. 141). 

Anhydro-bases, of alkyl thio- and seleno-pyrylium salts, 60, 119... 

Alkyl Thio-cyanates Alkyl Iso-thio-cyanates.—In the alkyl derivatives of thio-cyanic acid we again have isomerism exactly analogous to that in the unknown cyanates and the known iso-cyanates. 

This compound undergoes rearrangement the same as ammonium cyanate and thio-urea is obtained. With a soluble mercuric salt ammonium thiocyanate precipitates mercuric thio-cyanate which on heating swells up into phantastic shapes which are known as Pharaoh s serpents. The alkyl thio-cyanates are known and have been discussed (p. 74). Allyl-thio-cyanate is a constituent of oil of garlic. These... 

Thio-carbamic acid ester Alkyl thio-urea... 

Modica, M., Santagati, M., Russo, F., Parotti, L., Degioia, L., Selvaggini, C., Salmona, M. and Mennini, T. (1997). [[(Arylpiperazinyl)alkyl]thio]thieno[2,3-d]pyrimidinone Derivatives as High-Affinity, Selective 5-HTla Receptor Ligands. J.Med.Chem.,40,574-585. 

Alkylation of thiols.2 Dimethylfonnamide dimethyl acetal reacts with heterocyclic mercapto derivatives in boiling benzene or acetonitrile to give the corresponding alkyl-thio derivatives in excellent yields ... 

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